Defect-Driven Surface Reconstruction in High-Entropy Antiperovskite to Generate Mott-Schottky Interface for Boosting Oxygen Evolution.

Abstract

Anion exchange membrane (AEM) water electrolysis is a promising strategy for green hydrogen production, which enables the use of non-precious-metal catalysts. However, the activity and stability of oxygen evolution reaction (OER) catalysts are far from meeting the requirements of AEM water electrolysis at high current density. Herein, we report a high-entropy antiperovskite InN(NiCoFeCrV)₃ on nickel foam (denoted as InN(NiCoFeCrV)₃@NF) as a structurally integrated electrode for boosting the OER process. The high-entropy-driven elemental synergy effectively promotes the reconstruction dynamics and creates more active sites. The leaching of Cr/V triggers surface reconstruction to generate oxyhydroxides as the real active phases. Subsequently, the Mott-Schottky heterojunctions are established at the interface of oxyhydroxides and InN(NiCoFeCrV)₃, which creates a built-in electric field and offers a fast charge transfer path. Moreover, the high-entropy effect modulates the electronic structure and optimizes the OER process. The combined high conductivity and structural stability of InN(NiCoFeCrV)₃ enable efficient and durable water oxidation at high current densities. The InN(NiCoFeCrV)₃@NF electrode exhibits an ultralow overpotential of 279 mV at 100 mA cm^-2. The integrated AEM electrolyzer with InN(NiCoFeCrV)₃@NF shows an ultralow cell voltage of 1.70 V to achieve a high current density of 500 mA cm^-2 with outstanding stability for over 400 h. This work not only reports a strategy to design highly active and stable OER electrocatalysts for AEM electrolyzers but also provides insights into the charge transfer mechanism of antiperovskites.